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How do the French get away with a clean bill of heart health despite
a diet loaded with saturated fats? Scientists have long suspected that
the answer to the so-called "French paradox" lies in red wine. Now, the
results of a new study bring them closer to understanding why. Writing
this week in the online, open-access journal Public Library of Science
(PLoS) ONE, researchers from industry and academia, including the
University of Wisconsin-Madison and the University of Florida, report
that low doses of resveratrol -- a natural constituent of grapes,
pomegranates, red wine and other foods -- can potentially boost the
quality of life by improving heart health in old age.
The scientists included small amounts of resveratrol in the diets of
middle-aged mice and found that the compound has a widespread influence
on the genetic causes of aging. Specifically, the researchers found
that low doses of resveratrol mimic the heart-healthy effects of what
is known as caloric restriction, diets with 20 to 30 percent fewer
calories than a typical diet. The new study is important because it
suggests that resveratrol and caloric restriction, which has been
widely studied in animals from spiders to humans, may govern the same
master genetic pathways related to aging.
"Caloric restriction is highly effective in extending life in many
species. If you provide species with less food, the regulated cellular
stress response of this healthy habit actually makes them live longer,"
says study author Christiaan Leeuwenburgh, chief of the division of
biology of aging at UF's Institute on Aging. "In this study, the
effects of low doses of resveratrol (on genes) were comparable to
caloric restriction, the hallmark for life extension."
Previous research has shown that high doses of resveratrol extend
life in invertebrates and prevent early death in mice given a high-fat
diet. The new study extends those findings, showing that resveratrol in
low doses, beginning in middle age, can elicit many of the same
benefits as a reduced-calorie diet.
"Resveratrol is active in much lower doses than previously thought,"
said Tomas Prolla, a UW professor of genetics and a senior author of
the new report.
The group explored the agent's influence on the heart, muscle and
brain by looking to see which genes were switched on and off during the
aging process.
In the new study -- which compared the genetic responses of animals
to either restricted diets or normal diets including small doses of
resveratrol -- the similarities were remarkable, explains lead author
Jamie Barger of Madison, Wis.-based LifeGen Technologies, who
spearheaded the research.
In the heart, for example, there are at least 1,029 genes whose
functions change with age. In animals on restricted diets, 90 percent
of those heart genes experienced alterations in gene expression, while
low doses of resveratrol thwarted age-related change in 92 percent. The
new findings, say the study's authors, reveal how red wine's special
ingredient helps keep the heart young.
In short, the authors note that a glass of wine or food or
supplements containing even small doses of resveratrol are likely to
help stave off cardiac aging.
That finding, may also explain the remarkable heart health of people
who live in some regions of France where diets are soaked in saturated
fats but the incidence of heart disease, a major cause of mortality in
the United States, is low. In France, meals are traditionally
complemented with a glass of red wine.
"There must be a few master biochemical pathways activated in
response to caloric restriction, which in turn activate many other
pathways," explained Prolla. "And resveratrol seems to activate some of
these master pathways as well."
Resveratrol is currently sold over-the-counter as a nutritional
supplement with supposed anti-cancer, anti-viral, anti-inflammatory and
anti-aging benefits, although few scientific studies have verified
these claims in humans. That may soon change: Researchers at the
University of Florida hope to explore the effects of resveratrol on
older people in a phase 1 clinical trial, set to begin this summer.
The study will assess the supplement's effects on memory, physical
performance, inflammation and oxidative damage, according to Steve
Anton, a principal investigator of the upcoming trial and an assistant
professor of aging and geriatrics in the UF College of Medicine.
Mitochondria, the tiny power plants that keep a cell functioning,
are especially vulnerable to the oxidative damage that accumulates
during the aging process.
"In animal studies, (resveratrol) seems to promote mitochondrial
health," said Todd Manini, also a principal investigator of the
upcoming trial and an assistant professor of aging and geriatrics in
the UF College of Medicine. "Mitochondria are everywhere: They're in
the brain, in the muscle, the liver. So it could have kind of a global
impact on many different organ systems."
Source: University of Florida. Retrieved June 04, 2008.
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